Let me present you a simple analog yet powerful +40A constant current, one-way fully proportional Electronic Speed Controller for brushed electric motors. With added water cooling in boats it can handle even higher currents. RDS(ON) = 0.003 Ω.
   Like most other ESCs, this one is built up using N-channel Power MOSFET's because of their good characteristics (low DS resistance). Since this ESC has no reverse, it is not meant to be used in R/C cars or boats if reversed motor run is needed. It is more suitable for R/C airplanes. It has no BEC circuit therefore you must power the receiver and the servos from a different source. You can either use a separate battery pack or a standalone BEC (Battery Eliminator Circuit - I / II) for this purpose. The 4N25 opto-coupler used in the device electronically isolates the ESC from the Receiver thus eliminates possible radio interferences caused by the motor and protects the receiver in case of a malfunction as well.
   The input operating voltage range goes from 7.2 to 19.2 Volts or from 6 to 16 NiCd/NiMH cells.

   I don't want to go into how the controller works, I instead present you the schematic diagram, the components layout, the PCB layout, the components list or the bill of materials, some pictures of my own ESC, and provide you with other useful information. Hopefully everything you need to build this controller.
   I hope you find these pages useful and I wish you good luck in your work! If you need additional help have comments or suggestions regarding the controller feel free to contact me.

   For easier navigation use the at the top of each page.
   Latest changes:
      (19.07.06) Added 11 new pictures to the Hydromie gallery. Click here.
      (24.05.06) Added new gallery: The Field-Box Gallery with 20 pictures. Click here.
      (22.11.05) Added a PDF schematic diagram - the updated version. Click here.
      (21.11.05) Added a PDF alternative for the PCB layout. Click here.